Hours after the White House released a letter written by President Donald Trump to North Korean leader Kim Jong Un canceling the planned nuclear summit next month, Trump called the developments "a setback for North Korea and a setback for the world."

Trump said the current tough sanctions and 'maximum pressure campaign will continue' against North Korea.

Speaking in the Roosevelt Room, said he is "waiting" to see if North Korean leader Kim Jong Un will again "engage in constructive dialogue."

And he opened the door for diplomacy Thursday, saying the summit could be rescheduled.

But Trump insisted that Kim reach out, placing the blame on the North Korean leader for the collapse of negotiations.

Trump and Kim had been slated to meet June 12 in which White House officials had hoped would be a historic diplomatic breakthrough for the president.